Principle of Insulin
Insulin lowers blood glucose levels by promoting glucose uptake in peripheral tissues and inhibiting hepatic glucose output.
The bioassay evaluates the hypoglycemic effect of a test preparation vs. a standard insulin preparation.
Methods
Rabbit Method (Hypoglycemic Convulsion Method)
Procedure:
Preparation: Rabbits fasted for 18–24 hours (water allowed).
Dosing: Standard insulin administered intravenously or subcutaneously; test insulin given to a separate group.
Observations: Monitor for hypoglycemic convulsions, coma, or measure blood glucose levels at intervals.
Potency Determination: Compare ED50 values or onset time for hypoglycemic symptoms between test and standard samples using dose-response curves.
Potency Determination: Compare the time to convulsion/coma or reduction in blood glucose for standard vs. test.
Mouse Blood Glucose Method:
Procedure:
Preparation: Mice fasted for 6–8 hours.
Dosing: Graded doses of standard insulin and test insulin administered.
Observations: Measure % drop in blood glucose at 30, 60, and 90 minutes.
Data Analysis: Compare dose-response curves for test and standard insulin to determine potency.
Potency Determination: Plot the dose-response for blood glucose drop against the standard and test preparations.